tests/drivers/saul_drivers: enable gp8403 and 8302

These two drivers ensure that a VDAC and IDAC capabilities are included.

Author: basilfx

tests/drivers/saul_drivers/Makefile

@@ -28,6 +28,10 @@ endif
 ifneq (,$(filter bme680,$(DRIVERS)))
   USEMODULE += bme680_i2c
 endif
+ifneq (,$(filter gp8xxx,$(DRIVERS)))
+  USEMODULE += gp8403
+  USEMODULE += gp8302
+endif
 ifneq (,$(filter lm75,$(DRIVERS)))
   USEMODULE += tmp1075
 endif